What the FDA labels say about taking them together
Doxycycline and tetracycline
Doxycycline's FDA label of July 25, 2025 names tetracycline in its warnings section; the tetracycline label PlainMeds reads does not name doxycycline. The doxycycline label: “A decrease in fibula growth rate has been observed in premature infants given oral tetracycline in doses of 25 mg/kg every 6 hours.”
Check it at the source: the doxycycline FDA label on DailyMed (effective July 25, 2025, Chartwell RX, LLC.); the tetracycline FDA label on DailyMed (effective March 18, 2025, Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc.).
What does the doxycycline label say about tetracycline?
Doxycycline label, warningsWARNINGS The use of drugs of the tetracycline class, including doxycycline, during tooth development (last half of pregnancy, infancy and childhood to the age of 8 years) may cause permanent discoloration of the teeth (yellow-gray-brown).
Doxycycline Hyclate label (Chartwell RX, LLC, June 30, 2026), warnings and precautionsA decrease in fibula growth rate has been observed in premature infants given oral tetracycline in doses of 25 mg/kg every 6 hours.
Oracea label (Galderma Laboratories, L.P., April 16, 2025), drug interactionsDRUG INTERACTIONS Patients on anticoagulant therapy may require downward adjustment of their anticoagulant dosage. ( 7.1 ) Some bacteriostatic drugs may interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracycline-class drugs in conjunction with penicillin. ( 7.2 ) The concurrent use of tetracycline and methoxyflurane has been reported to result in fatal renal toxicity.
Acticlate Cap label (Aqua Pharmaceuticals, November 28, 2017), drug interactionsPenthrane ® The concurrent use of tetracycline and Penthrane ® (methoxyflurane) has been reported to result in fatal renal toxicity.
Acticlate Cap label (Aqua Pharmaceuticals, November 28, 2017), warnings and precautionsPatients apt to be exposed to direct sunlight or ultraviolet light should be advised that this reaction can occur with tetracycline drugs, and treatment should be discontinued at the first evidence of skin erythema.
Source: FDA drug label (Doxycycline Hyclate, NDA205931), Chartwell RX, LLC, effective June 30, 2026 (SPL set fad03768-f1d2-459f-965e-0ec29f189f1f), via openFDA
Source: FDA drug label (Oracea, NDA050805), Galderma Laboratories, L.P., effective April 16, 2025 (SPL set aa15c93a-ff4c-447a-8a21-96da506d8997), via openFDA
Source: FDA drug label (Doxycycline Monohydrate), Chartwell RX, LLC., effective July 25, 2025 (SPL set 02aa8731-d40f-43d8-8b63-a79a0503f8db), via openFDA; the full label on DailyMed
What does the tetracycline label say about doxycycline?
Tetracycline's label (effective March 18, 2025) does not name doxycycline in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (tetracycline hydrochloride), Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc., effective March 18, 2025 (SPL set eaa5b1bd-0927-46e4-b941-32fcc492d258), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Doxycycline | Tetracycline | |
|---|---|---|
| Labeled for | Urinary tract infections, Bacterial infections, Acne | Bacterial infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.118 per tablet 100 mg tablet | $0.247 per capsule 250 mg capsule |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once